What size AC for Wenatchee, WA? 2.5 tons for 2,000 sq ft

What size AC a 2,000 sq ft house in Wenatchee needs

2.5 tons central AC or heat pump, about 30,300 BTU/hr of load

The 20 BTU per square foot chart would put in 3.5 tons, about 38% more than this climate needs. An oversized unit cools the air fast, shuts off before it pulls moisture out, and leaves the house cold and clammy.

If a contractor quotes you more than 2.5 tons for an average 2,000 sq ft house here, ask to see the Manual J load calculation behind it before you sign. That works out to one ton per 791 square feet in this climate. For a single room, size by the room: 15.2 BTU/hr per square foot.

The climate it is sized for

Climate from NOAA's 1991 to 2020 normals at Wenatchee Pangborn Mem Airport (6.6 mi away). Jul is the hottest month, averaging a high of 87.6°F and a low of 61.8°F, with about 35 days a year at 90°F or more. That gives a design temperature of 93°F against 75°F inside.

What it costs to run

About 1,053 kWh a year at SEER2 14.3, or roughly $152 at Washington's average residential rate of 14.42¢ per kWh. Cooling runs 4 months of the year here.

What drives the load in Wenatchee

Of the 30,300 BTU/hr, 12,960 comes through walls, roof and windows on a 93°F afternoon (43%), 13,000 is sun on the house (43%), 2,120 is four people and their appliances, and 2,200 is moisture the coil has to wring out of Wenatchee's summer air (7%).

Sun is the biggest share here, more than heat through the walls, so shading west windows and a light roof cut the size you need more than extra insulation would. Sensible heat totals 28,080 BTU/hr before the moisture allowance.

Other house sizes in Wenatchee

Single rooms with a window or mini-split unit: a 150 sq ft bedroom needs about 2,300 BTU/hr; a 350 sq ft living room needs about 5,300 BTU/hr; a 600 sq ft open plan kitchen and family room needs about 9,100 BTU/hr.

Month by month in Wenatchee

Jul alone uses 38% of the year's cooling energy. The unit runs the equivalent of 496 hours a year at full output.

Wenatchee against nearby cities

Of 91 Washington cities here, Wenatchee has the 8th highest cooling load. The range runs from Burlington at 15,700 BTU/hr to Kennewick at 32,900.

Where Wenatchee's weather numbers come from

The nearest NOAA station with full 1991 to 2020 normals is Wenatchee Pangborn Mem Airport, 6.6 miles from the center of Wenatchee at 1,238 ft above sea level. That is close enough that the station's summers are Wenatchee's summers.

1 other city uses the same station and get the same climate inputs. The closest to Wenatchee: East Wenatchee (2 mi away, 4.1 mi from the station). Wenatchee is farther from the station than 1 of them.

The sun over Wenatchee in late July

At 47.44°N, the noon sun on 21 July stands 63.0° above the horizon over Wenatchee and the day runs 15 h 11 min from sunrise to sunset. A lower noon sun puts more of the day's heat on east and west walls than on the roof, which is why shading west glass pays off here. Long days mean the house keeps gaining heat into the evening, well after the outdoor peak.

35,401 people live in Wenatchee, the 34th largest of the 91 Washington cities sized on this site. Coordinates used: 47.4360, -120.3293.

Wenatchee AC sizing questions